How can I redirect the same message to both stdoud and stderr (without temporary file)

Question

It is easy to redirect stdout or stderr to the same output (file or one of the 2 std output) with a 1>&1,>&2 and/or >file but is there a way to send the same output to both the std output in KSH (like | tee File but with &2 as file) ?

Answer 1

#!/bin/ksh

function mytee { 
        while read -r x ; do
                print "${x}"
                print "${x}" >&2
        done
}

echo "TestMyTee
second line
and a * character" | mytee

# Really stdout and stderr?
echo "TestMyTee
second line
and a * character" | mytee 1>mystdout 2>mystderr

Edited: replaced [read] and [echo] by [read -r] and [print]

Answer 2

Response on Unix & Linux

Post: How can I redirect the same message to both stdoud and stderr (without temporary object)

by Stéphane Chazelas

{ your-code } | perl -pe 'print STDERR'